<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
<textarea id="code">return "hi";</textarea>
<button id="button">Run</button>
<pre id="output"></pre>

<script>
  // Your code here.
</script>

</body>
</html>